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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.3 05-Jul-07
5    ---------------------
6    
7     1. In the rejigging of the build system that eventually resulted in 7.1, the
8        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
9        brackets there is not right, since it causes compilers to look for an
10        installed pcre.h, not the version that is in the source that is being
11        compiled (which of course may be different). I have changed it back to:
12    
13          #include "pcre.h"
14    
15        I have a vague recollection that the change was concerned with compiling in
16        different directories, but in the new build system, that is taken care of
17        by the VPATH setting the Makefile.
18    
19    
20    
21    Version 7.2 19-Jun-07
22    ---------------------
23    
24     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
25        which is apparently normally available under Windows.
26    
27     2. Re-jig the pcregrep tests with different newline settings in an attempt
28        to make them independent of the local environment's newline setting.
29    
30     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
31    
32     4. Some of the "internals" tests were previously cut out when the link size
33        was not 2, because the output contained actual offsets. The recent new
34        "Z" feature of pcretest means that these can be cut out, making the tests
35        usable with all link sizes.
36    
37     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
38        stack recursion. This gives a massive performance boost under BSD, but just
39        a small improvement under Linux. However, it saves one field in the frame
40        in all cases.
41    
42     6. Added more features from the forthcoming Perl 5.10:
43    
44        (a) (?-n) (where n is a string of digits) is a relative subroutine or
45            recursion call. It refers to the nth most recently opened parentheses.
46    
47        (b) (?+n) is also a relative subroutine call; it refers to the nth next
48            to be opened parentheses.
49    
50        (c) Conditions that refer to capturing parentheses can be specified
51            relatively, for example, (?(-2)... or (?(+3)...
52    
53        (d) \K resets the start of the current match so that everything before
54            is not part of it.
55    
56        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
57    
58        (f) \g{name} is another synonym - part of Perl 5.10's unification of
59            reference syntax.
60    
61        (g) (?| introduces a group in which the numbering of parentheses in each
62            alternative starts with the same number.
63    
64        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
65    
66     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
67        PCRE_INFO_JCHANGED.
68    
69     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
70        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
71        for detecting groups that can match an empty string.
72    
73     9. A pattern with a very large number of alternatives (more than several
74        hundred) was running out of internal workspace during the pre-compile
75        phase, where pcre_compile() figures out how much memory will be needed. A
76        bit of new cunning has reduced the workspace needed for groups with
77        alternatives. The 1000-alternative test pattern now uses 12 bytes of
78        workspace instead of running out of the 4096 that are available.
79    
80    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
81    
82    11. Applied patch from Google to remove an optimization that didn't quite work.
83        The report of the bug said:
84    
85          pcrecpp::RE("a*").FullMatch("aaa") matches, while
86          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
87          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
88    
89    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
90        it matched the wrong number of bytes.
91    
92    
93    Version 7.1 24-Apr-07
94    ---------------------
95    
96     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
97        that is more "standard", making use of automake and other Autotools. There
98        is some re-arrangement of the files and adjustment of comments consequent
99        on this.
100    
101     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
102        for recursive directory scanning broke on some systems because the files
103        are not scanned in any specific order and on different systems the order
104        was different. A call to "sort" has been inserted into RunGrepTest for the
105        approprate test as a short-term fix. In the longer term there may be an
106        alternative.
107    
108     3. I had an email from Eric Raymond about problems translating some of PCRE's
109        man pages to HTML (despite the fact that I distribute HTML pages, some
110        people do their own conversions for various reasons). The problems
111        concerned the use of low-level troff macros .br and .in. I have therefore
112        removed all such uses from the man pages (some were redundant, some could
113        be replaced by .nf/.fi pairs). The 132html script that I use to generate
114        HTML has been updated to handle .nf/.fi and to complain if it encounters
115        .br or .in.
116    
117     4. Updated comments in configure.ac that get placed in config.h.in and also
118        arranged for config.h to be included in the distribution, with the name
119        config.h.generic, for the benefit of those who have to compile without
120        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
121    
122     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
123        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
124        makevp.bat for the current PCRE, using the additional files
125        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
126    
127     6. A Windows user reported a minor discrepancy with test 2, which turned out
128        to be caused by a trailing space on an input line that had got lost in his
129        copy. The trailing space was an accident, so I've just removed it.
130    
131     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
132        that is needed.
133    
134     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
135        as "const" (a) because they are and (b) because it helps the PHP
136        maintainers who have recently made a script to detect big data structures
137        in the php code that should be moved to the .rodata section. I remembered
138        to update Builducptable as well, so it won't revert if ucptable.h is ever
139        re-created.
140    
141     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
142        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
143        order to be able to cut out the UTF-8 tables in the latter when UTF-8
144        support is not required. This saves 1.5-2K of code, which is important in
145        some applications.
146    
147        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
148        so as not to refer to the tables, even though these functions will never be
149        called when UTF-8 support is disabled. Otherwise there are problems with a
150        shared library.
151    
152    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
153    
154        (a) It was defining its arguments as char * instead of void *.
155    
156        (b) It was assuming that all moves were upwards in memory; this was true
157            a long time ago when I wrote it, but is no longer the case.
158    
159        The emulated memove() is provided for those environments that have neither
160        memmove() nor bcopy(). I didn't think anyone used it these days, but that
161        is clearly not the case, as these two bugs were recently reported.
162    
163    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
164        and Detrail to create the HTML documentation, the .txt form of the man
165        pages, and it removes trailing spaces from listed files. It also creates
166        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
167        case, it wraps all the #defines with #ifndefs. This script should be run
168        before "make dist".
169    
170    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
171        with Unicode property support.
172    
173        (a) For a maximizing quantifier, if the two different cases of the
174            character were of different lengths in their UTF-8 codings (there are
175            some cases like this - I found 11), and the matching function had to
176            back up over a mixture of the two cases, it incorrectly assumed they
177            were both the same length.
178    
179        (b) When PCRE was configured to use the heap rather than the stack for
180            recursion during matching, it was not correctly preserving the data for
181            the other case of a UTF-8 character when checking ahead for a match
182            while processing a minimizing repeat. If the check also involved
183            matching a wide character, but failed, corruption could cause an
184            erroneous result when trying to check for a repeat of the original
185            character.
186    
187    13. Some tidying changes to the testing mechanism:
188    
189        (a) The RunTest script now detects the internal link size and whether there
190            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
191            values substituted by "configure". (The RunGrepTest script already did
192            this for UTF-8.) The configure.ac script no longer substitutes the
193            relevant variables.
194    
195        (b) The debugging options /B and /D in pcretest show the compiled bytecode
196            with length and offset values. This means that the output is different
197            for different internal link sizes. Test 2 is skipped for link sizes
198            other than 2 because of this, bypassing the problem. Unfortunately,
199            there was also a test in test 3 (the locale tests) that used /B and
200            failed for link sizes other than 2. Rather than cut the whole test out,
201            I have added a new /Z option to pcretest that replaces the length and
202            offset values with spaces. This is now used to make test 3 independent
203            of link size. (Test 2 will be tidied up later.)
204    
205    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
206        segmentation fault instead of returning the appropriate error message.
207    
208    15. In multiline mode when the newline sequence was set to "any", the pattern
209        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
210        This doesn't seem right; it now treats the CRLF combination as the line
211        ending, and so does not match in that case. It's only a pattern such as ^$
212        that would hit this one: something like ^ABC$ would have failed after \r
213        and then tried again after \r\n.
214    
215    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
216        in an attempt to make files that differ only in their line terminators
217        compare equal. This works on Linux.
218    
219    17. Under certain error circumstances pcregrep might try to free random memory
220        as it exited. This is now fixed, thanks to valgrind.
221    
222    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
223        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
224        was because its rules for how to advance for /g after matching an empty
225        string at the end of a line did not allow for this case. They now check for
226        it specially.
227    
228    20. pcretest is supposed to handle patterns and data of any length, by
229        extending its buffers when necessary. It was getting this wrong when the
230        buffer for a data line had to be extended.
231    
232    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
233        CRLF as a newline sequence.
234    
235    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
236        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
237        I have nevertheless tidied it up.
238    
239    23. Added some casts to kill warnings from HP-UX ia64 compiler.
240    
241    24. Added a man page for pcre-config.
242    
243    
244    Version 7.0 19-Dec-06
245    ---------------------
246    
247     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
248        moving to gcc 4.1.1.
249    
250     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
251        sys/time.h, which is documented as needed for this function. It doesn't
252        seem to matter on Linux, but it showed up on some releases of OS X.
253    
254     3. It seems that there are systems where bytes whose values are greater than
255        127 match isprint() in the "C" locale. The "C" locale should be the
256        default when a C program starts up. In most systems, only ASCII printing
257        characters match isprint(). This difference caused the output from pcretest
258        to vary, making some of the tests fail. I have changed pcretest so that:
259    
260        (a) When it is outputting text in the compiled version of a pattern, bytes
261            other than 32-126 are always shown as hex escapes.
262    
263        (b) When it is outputting text that is a matched part of a subject string,
264            it does the same, unless a different locale has been set for the match
265            (using the /L modifier). In this case, it uses isprint() to decide.
266    
267     4. Fixed a major bug that caused incorrect computation of the amount of memory
268        required for a compiled pattern when options that changed within the
269        pattern affected the logic of the preliminary scan that determines the
270        length. The relevant options are -x, and -i in UTF-8 mode. The result was
271        that the computed length was too small. The symptoms of this bug were
272        either the PCRE error "internal error: code overflow" from pcre_compile(),
273        or a glibc crash with a message such as "pcretest: free(): invalid next
274        size (fast)". Examples of patterns that provoked this bug (shown in
275        pcretest format) are:
276    
277          /(?-x: )/x
278          /(?x)(?-x: \s*#\s*)/
279          /((?i)[\x{c0}])/8
280          /(?i:[\x{c0}])/8
281    
282        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
283        is now done differently.
284    
285     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
286        wrapper classes; (b) implement a new function in the C++ scanner that is
287        more efficient than the old way of doing things because it avoids levels of
288        recursion in the regex matching; (c) add a paragraph to the documentation
289        for the FullMatch() function.
290    
291     6. The escape sequence \n was being treated as whatever was defined as
292        "newline". Not only was this contrary to the documentation, which states
293        that \n is character 10 (hex 0A), but it also went horribly wrong when
294        "newline" was defined as CRLF. This has been fixed.
295    
296     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
297        was being set to -1 for the "end of line" case (supposedly a value that no
298        character can have). Though this value is never used (the check for end of
299        line is "zero bytes in current character"), it caused compiler complaints.
300        I've changed it to 0xffffffff.
301    
302     8. In pcre_version.c, the version string was being built by a sequence of
303        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
304        string (as it is for production releases) called a macro with an empty
305        argument. The C standard says the result of this is undefined. The gcc
306        compiler treats it as an empty string (which was what was wanted) but it is
307        reported that Visual C gives an error. The source has been hacked around to
308        avoid this problem.
309    
310     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
311        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
312        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
313        of them did).
314    
315    10. Originally, pcretest opened its input and output without "b"; then I was
316        told that "b" was needed in some environments, so it was added for release
317        5.0 to both the input and output. (It makes no difference on Unix-like
318        systems.) Later I was told that it is wrong for the input on Windows. I've
319        now abstracted the modes into two macros, to make it easier to fiddle with
320        them, and removed "b" from the input mode under Windows.
321    
322    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
323    
324    12. Added -help and --help to pcretest as an official way of being reminded
325        of the options.
326    
327    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
328        and pcrecpp.cc because they annoy compilers at high warning levels.
329    
330    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
331    
332    15. Fixed an occurrence of == in configure.ac that should have been = (shell
333        scripts are not C programs :-) and which was not noticed because it works
334        on Linux.
335    
336    16. pcretest is supposed to handle any length of pattern and data line (as one
337        line or as a continued sequence of lines) by extending its input buffer if
338        necessary. This feature was broken for very long pattern lines, leading to
339        a string of junk being passed to pcre_compile() if the pattern was longer
340        than about 50K.
341    
342    17. I have done a major re-factoring of the way pcre_compile() computes the
343        amount of memory needed for a compiled pattern. Previously, there was code
344        that made a preliminary scan of the pattern in order to do this. That was
345        OK when PCRE was new, but as the facilities have expanded, it has become
346        harder and harder to keep it in step with the real compile phase, and there
347        have been a number of bugs (see for example, 4 above). I have now found a
348        cunning way of running the real compile function in a "fake" mode that
349        enables it to compute how much memory it would need, while actually only
350        ever using a few hundred bytes of working memory and without too many
351        tests of the mode. This should make future maintenance and development
352        easier. A side effect of this work is that the limit of 200 on the nesting
353        depth of parentheses has been removed (though this was never a serious
354        limitation, I suspect). However, there is a downside: pcre_compile() now
355        runs more slowly than before (30% or more, depending on the pattern). I
356        hope this isn't a big issue. There is no effect on runtime performance.
357    
358    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
359        newline (only possible for the last line of a file) and it was a
360        pattern that set a locale (followed by /Lsomething), pcretest crashed.
361    
362    19. Added additional timing features to pcretest. (1) The -tm option now times
363        matching only, not compiling. (2) Both -t and -tm can be followed, as a
364        separate command line item, by a number that specifies the number of
365        repeats to use when timing. The default is 50000; this gives better
366        precision, but takes uncomfortably long for very large patterns.
367    
368    20. Extended pcre_study() to be more clever in cases where a branch of a
369        subpattern has no definite first character. For example, (a*|b*)[cd] would
370        previously give no result from pcre_study(). Now it recognizes that the
371        first character must be a, b, c, or d.
372    
373    21. There was an incorrect error "recursive call could loop indefinitely" if
374        a subpattern (or the entire pattern) that was being tested for matching an
375        empty string contained only one non-empty item after a nested subpattern.
376        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
377        incorrectly, because the \d was being skipped in the check.
378    
379    22. The pcretest program now has a new pattern option /B and a command line
380        option -b, which is equivalent to adding /B to every pattern. This causes
381        it to show the compiled bytecode, without the additional information that
382        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
383        is the same as /B/I).
384    
385    23. A new optimization is now able automatically to treat some sequences such
386        as a*b as a*+b. More specifically, if something simple (such as a character
387        or a simple class like \d) has an unlimited quantifier, and is followed by
388        something that cannot possibly match the quantified thing, the quantifier
389        is automatically "possessified".
390    
391    24. A recursive reference to a subpattern whose number was greater than 39
392        went wrong under certain circumstances in UTF-8 mode. This bug could also
393        have affected the operation of pcre_study().
394    
395    25. Realized that a little bit of performance could be had by replacing
396        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
397    
398    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
399    
400    27. Possessive quantifiers such as a++ were previously implemented by turning
401        them into atomic groups such as ($>a+). Now they have their own opcodes,
402        which improves performance. This includes the automatically created ones
403        from 23 above.
404    
405    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
406        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
407        the first matched character to be a colon. This applied both to named and
408        numbered groups.
409    
410    29. The ucpinternal.h header file was missing its idempotency #ifdef.
411    
412    30. I was sent a "project" file called libpcre.a.dev which I understand makes
413        building PCRE on Windows easier, so I have included it in the distribution.
414    
415    31. There is now a check in pcretest against a ridiculously large number being
416        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
417        loop, the loop is abandoned.
418    
419    32. Forward references to subpatterns in conditions such as (?(2)...) where
420        subpattern 2 is defined later cause pcre_compile() to search forwards in
421        the pattern for the relevant set of parentheses. This search went wrong
422        when there were unescaped parentheses in a character class, parentheses
423        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
424    
425    33. "Subroutine" calls and backreferences were previously restricted to
426        referencing subpatterns earlier in the regex. This restriction has now
427        been removed.
428    
429    34. Added a number of extra features that are going to be in Perl 5.10. On the
430        whole, these are just syntactic alternatives for features that PCRE had
431        previously implemented using the Python syntax or my own invention. The
432        other formats are all retained for compatibility.
433    
434        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
435            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
436            also .NET compatible.
437    
438        (b) A recursion or subroutine call to a named group can now be defined as
439            (?&name) as well as (?P>name).
440    
441        (c) A backreference to a named group can now be defined as \k<name> or
442            \k'name' as well as (?P=name). The new forms, as well as being in Perl
443            5.10, are also .NET compatible.
444    
445        (d) A conditional reference to a named group can now use the syntax
446            (?(<name>) or (?('name') as well as (?(name).
447    
448        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
449            groups (named and numbered) that are never evaluated inline, but can be
450            called as "subroutines" from elsewhere. In effect, the DEFINE condition
451            is always false. There may be only one alternative in such a group.
452    
453        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
454            as the simple (?(R). The condition is true only if the most recent
455            recursion is that of the given number or name. It does not search out
456            through the entire recursion stack.
457    
458        (g) The escape \gN or \g{N} has been added, where N is a positive or
459            negative number, specifying an absolute or relative reference.
460    
461    35. Tidied to get rid of some further signed/unsigned compiler warnings and
462        some "unreachable code" warnings.
463    
464    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
465        things, this adds five new scripts.
466    
467    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
468        There were also incompatibilities regarding the handling of \Q..\E inside
469        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
470        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
471    
472    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
473        matches an empty string, and forcibly breaks the loop. There were bugs in
474        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
475        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
476        separate and independent bugs (that affected different cases) have been
477        fixed.
478    
479    39. Refactored the code to abolish the use of different opcodes for small
480        capturing bracket numbers. This is a tidy that I avoided doing when I
481        removed the limit on the number of capturing brackets for 3.5 back in 2001.
482        The new approach is not only tidier, it makes it possible to reduce the
483        memory needed to fix the previous bug (38).
484    
485    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
486        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
487        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
488        mode.
489    
490    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
491        report.
492    
493    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
494        copy construction and assignment in the C++ wrapper.
495    
496    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
497        couple of bugs that could have given wrong results in the "--newline=crlf"
498        case.
499    
500    44. Added a number of casts and did some reorganization of signed/unsigned int
501        variables following suggestions from Dair Grant. Also renamed the variable
502        "this" as "item" because it is a C++ keyword.
503    
504    45. Arranged for dftables to add
505    
506          #include "pcre_internal.h"
507    
508        to pcre_chartables.c because without it, gcc 4.x may remove the array
509        definition from the final binary if PCRE is built into a static library and
510        dead code stripping is activated.
511    
512    46. For an unanchored pattern, if a match attempt fails at the start of a
513        newline sequence, and the newline setting is CRLF or ANY, and the next two
514        characters are CRLF, advance by two characters instead of one.
515    
516    
517    Version 6.7 04-Jul-06
518    ---------------------
519    
520     1. In order to handle tests when input lines are enormously long, pcretest has
521        been re-factored so that it automatically extends its buffers when
522        necessary. The code is crude, but this _is_ just a test program. The
523        default size has been increased from 32K to 50K.
524    
525     2. The code in pcre_study() was using the value of the re argument before
526        testing it for NULL. (Of course, in any sensible call of the function, it
527        won't be NULL.)
528    
529     3. The memmove() emulation function in pcre_internal.h, which is used on
530        systems that lack both memmove() and bcopy() - that is, hardly ever -
531        was missing a "static" storage class specifier.
532    
533     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
534        containing an extended class (one that cannot be represented by a bitmap
535        because it contains high-valued characters or Unicode property items, e.g.
536        [\pZ]). Almost always one would set UTF-8 mode when processing such a
537        pattern, but PCRE should not loop if you do not (it no longer does).
538        [Detail: two cases were found: (a) a repeated subpattern containing an
539        extended class; (b) a recursive reference to a subpattern that followed a
540        previous extended class. It wasn't skipping over the extended class
541        correctly when UTF-8 mode was not set.]
542    
543     5. A negated single-character class was not being recognized as fixed-length
544        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
545        compile error "lookbehind assertion is not fixed length".
546    
547     6. The RunPerlTest auxiliary script was showing an unexpected difference
548        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
549        write a Perl script that can interpret lines of an input file either as
550        byte characters or as UTF-8, which is what "perltest" was being required to
551        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
552        can't do is switch easily at run time between having the "use utf8;" pragma
553        or not. In the end, I fudged it by using the RunPerlTest script to insert
554        "use utf8;" explicitly for the UTF-8 tests.
555    
556     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
557        the end of the subject string, contrary to the documentation and to what
558        Perl does. This was true of both matching functions. Now it matches only at
559        the start of the subject and immediately after *internal* newlines.
560    
561     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
562        a pointer to an int instead of a pointer to an unsigned long int. This
563        caused problems on 64-bit systems.
564    
565     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
566        instance of the 'standard' template library not being so standard".
567    
568    10. There was no check on the number of named subpatterns nor the maximum
569        length of a subpattern name. The product of these values is used to compute
570        the size of the memory block for a compiled pattern. By supplying a very
571        long subpattern name and a large number of named subpatterns, the size
572        computation could be caused to overflow. This is now prevented by limiting
573        the length of names to 32 characters, and the number of named subpatterns
574        to 10,000.
575    
576    11. Subpatterns that are repeated with specific counts have to be replicated in
577        the compiled pattern. The size of memory for this was computed from the
578        length of the subpattern and the repeat count. The latter is limited to
579        65535, but there was no limit on the former, meaning that integer overflow
580        could in principle occur. The compiled length of a repeated subpattern is
581        now limited to 30,000 bytes in order to prevent this.
582    
583    12. Added the optional facility to have named substrings with the same name.
584    
585    13. Added the ability to use a named substring as a condition, using the
586        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
587        are numbers (not recommended). Forward references are permitted.
588    
589    14. Added forward references in named backreferences (if you see what I mean).
590    
591    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
592        pattern could run off the end of the subject. For example, the pattern
593        "(?s)(.{1,5})"8 did this with the subject "ab".
594    
595    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
596        PCRE_CASELESS was set when matching characters that were quantified with ?
597        or *.
598    
599    17. A character class other than a single negated character that had a minimum
600        but no maximum quantifier - for example [ab]{6,} - was not handled
601        correctly by pce_dfa_exec(). It would match only one character.
602    
603    18. A valid (though odd) pattern that looked like a POSIX character
604        class but used an invalid character after [ (for example [[,abc,]]) caused
605        pcre_compile() to give the error "Failed: internal error: code overflow" or
606        in some cases to crash with a glibc free() error. This could even happen if
607        the pattern terminated after [[ but there just happened to be a sequence of
608        letters, a binary zero, and a closing ] in the memory that followed.
609    
610    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
611        over the years. Originally (before any Unicode support), just the bottom 8
612        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
613        output from "man perlunicode" includes this:
614    
615          The regular expression compiler produces polymorphic opcodes.  That
616          is, the pattern adapts to the data and automatically switches to
617          the Unicode character scheme when presented with Unicode data--or
618          instead uses a traditional byte scheme when presented with byte
619          data.
620    
621        Sadly, a wide octal escape does not cause a switch, and in a string with
622        no other multibyte characters, these octal escapes are treated as before.
623        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
624        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
625        Unicode string.
626    
627        I have not perpetrated such confusion in PCRE. Up till now, it took just
628        the bottom 8 bits, as in old Perl. I have now made octal escapes with
629        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
630        translate to the appropriate multibyte character.
631    
632    29. Applied some refactoring to reduce the number of warnings from Microsoft
633        and Borland compilers. This has included removing the fudge introduced
634        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
635        a warning about an unused variable.
636    
637    21. PCRE has not included VT (character 0x0b) in the set of whitespace
638        characters since release 4.0, because Perl (from release 5.004) does not.
639        [Or at least, is documented not to: some releases seem to be in conflict
640        with the documentation.] However, when a pattern was studied with
641        pcre_study() and all its branches started with \s, PCRE still included VT
642        as a possible starting character. Of course, this did no harm; it just
643        caused an unnecessary match attempt.
644    
645    22. Removed a now-redundant internal flag bit that recorded the fact that case
646        dependency changed within the pattern. This was once needed for "required
647        byte" processing, but is no longer used. This recovers a now-scarce options
648        bit. Also moved the least significant internal flag bit to the most-
649        significant bit of the word, which was not previously used (hangover from
650        the days when it was an int rather than a uint) to free up another bit for
651        the future.
652    
653    23. Added support for CRLF line endings as well as CR and LF. As well as the
654        default being selectable at build time, it can now be changed at runtime
655        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
656        specify that it is scanning data with non-default line endings.
657    
658    24. Changed the definition of CXXLINK to make it agree with the definition of
659        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
660    
661    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
662        recursions. This makes a big different to stack usage for some patterns.
663    
664    26. If a subpattern containing a named recursion or subroutine reference such
665        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
666        the space required for the compiled pattern went wrong and gave too small a
667        value. Depending on the environment, this could lead to "Failed: internal
668        error: code overflow at offset 49" or "glibc detected double free or
669        corruption" errors.
670    
671    27. Applied patches from Google (a) to support the new newline modes and (b) to
672        advance over multibyte UTF-8 characters in GlobalReplace.
673    
674    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
675        difference for some implementation of PCRE in some Windows version.
676    
677    29. Added some extra testing facilities to pcretest:
678    
679        \q<number>   in a data line sets the "match limit" value
680        \Q<number>   in a data line sets the "match recursion limt" value
681        -S <number>  sets the stack size, where <number> is in megabytes
682    
683        The -S option isn't available for Windows.
684    
685    
686    Version 6.6 06-Feb-06
687    ---------------------
688    
689     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
690        in pcreposix.h. I have copied the definition from pcre.h.
691    
692     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
693        because pcre.h is no longer a built file.
694    
695     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
696        not normally included in the compiled code.
697    
698    
699    Version 6.5 01-Feb-06
700    ---------------------
701    
702     1. When using the partial match feature with pcre_dfa_exec(), it was not
703        anchoring the second and subsequent partial matches at the new starting
704        point. This could lead to incorrect results. For example, with the pattern
705        /1234/, partially matching against "123" and then "a4" gave a match.
706    
707     2. Changes to pcregrep:
708    
709        (a) All non-match returns from pcre_exec() were being treated as failures
710            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
711            error message is output. Some extra information is given for the
712            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
713            probably the only errors that are likely to be caused by users (by
714            specifying a regex that has nested indefinite repeats, for instance).
715            If there are more than 20 of these errors, pcregrep is abandoned.
716    
717        (b) A binary zero was treated as data while matching, but terminated the
718            output line if it was written out. This has been fixed: binary zeroes
719            are now no different to any other data bytes.
720    
721        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
722            used to set a locale for matching. The --locale=xxxx long option has
723            been added (no short equivalent) to specify a locale explicitly on the
724            pcregrep command, overriding the environment variables.
725    
726        (d) When -B was used with -n, some line numbers in the output were one less
727            than they should have been.
728    
729        (e) Added the -o (--only-matching) option.
730    
731        (f) If -A or -C was used with -c (count only), some lines of context were
732            accidentally printed for the final match.
733    
734        (g) Added the -H (--with-filename) option.
735    
736        (h) The combination of options -rh failed to suppress file names for files
737            that were found from directory arguments.
738    
739        (i) Added the -D (--devices) and -d (--directories) options.
740    
741        (j) Added the -F (--fixed-strings) option.
742    
743        (k) Allow "-" to be used as a file name for -f as well as for a data file.
744    
745        (l) Added the --colo(u)r option.
746    
747        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
748            is not present by default.
749    
750     3. A nasty bug was discovered in the handling of recursive patterns, that is,
751        items such as (?R) or (?1), when the recursion could match a number of
752        alternatives. If it matched one of the alternatives, but subsequently,
753        outside the recursion, there was a failure, the code tried to back up into
754        the recursion. However, because of the way PCRE is implemented, this is not
755        possible, and the result was an incorrect result from the match.
756    
757        In order to prevent this happening, the specification of recursion has
758        been changed so that all such subpatterns are automatically treated as
759        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
760    
761     4. I had overlooked the fact that, in some locales, there are characters for
762        which isalpha() is true but neither isupper() nor islower() are true. In
763        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
764        and ordfeminine) are like this. This affected the treatment of \w and \W
765        when they appeared in character classes, but not when they appeared outside
766        a character class. The bit map for "word" characters is now created
767        separately from the results of isalnum() instead of just taking it from the
768        upper, lower, and digit maps. (Plus the underscore character, of course.)
769    
770     5. The above bug also affected the handling of POSIX character classes such as
771        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
772        permanent tables. Instead, the bit maps for such a class were previously
773        created as the appropriate unions of the upper, lower, and digit bitmaps.
774        Now they are created by subtraction from the [[:word:]] class, which has
775        its own bitmap.
776    
777     6. The [[:blank:]] character class matches horizontal, but not vertical space.
778        It is created by subtracting the vertical space characters (\x09, \x0a,
779        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
780        subtraction was done in the overall bitmap for a character class, meaning
781        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
782        be recognized. This bug has been fixed.
783    
784     7. Patches from the folks at Google:
785    
786          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
787          real life, but is still worth protecting against".
788    
789          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
790          regular expressions".
791    
792          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
793          have it.
794    
795          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
796          "configure" and the latter not, in order to fix a problem somebody had
797          with compiling the Arg class on HP-UX.
798    
799          (e) Improve the error-handling of the C++ wrapper a little bit.
800    
801          (f) New tests for checking recursion limiting.
802    
803     8. The pcre_memmove() function, which is used only if the environment does not
804        have a standard memmove() function (and is therefore rarely compiled),
805        contained two bugs: (a) use of int instead of size_t, and (b) it was not
806        returning a result (though PCRE never actually uses the result).
807    
808     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
809        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
810        returned instead of calling malloc() with an overflowing number that would
811        most likely cause subsequent chaos.
812    
813    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
814    
815    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
816        with this option is matched, the nmatch and pmatch options of regexec() are
817        ignored.
818    
819    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
820        provided in case anyone wants to the the POSIX interface with UTF-8
821        strings.
822    
823    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
824        C++ linking (needed for some HP-UX environments).
825    
826    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
827        (unused parameter) and in the pcre_printint() function (omitted "default"
828        switch label when the default is to do nothing).
829    
830    15. Added some code to make it possible, when PCRE is compiled as a C++
831        library, to replace subject pointers for pcre_exec() with a smart pointer
832        class, thus making it possible to process discontinuous strings.
833    
834    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
835        much the same function. They were added by different people who were trying
836        to make PCRE easy to compile on non-Unix systems. It has been suggested
837        that PCRE_EXPORT be abolished now that there is more automatic apparatus
838        for compiling on Windows systems. I have therefore replaced it with
839        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
840        defaults to "extern" for C or "extern C" for C++, which works fine on
841        Unix-like systems. It is now possible to override the value of PCRE_DATA_
842        SCOPE with something explicit in config.h. In addition:
843    
844        (a) pcreposix.h still had just "extern" instead of either of these macros;
845            I have replaced it with PCRE_DATA_SCOPE.
846    
847        (b) Functions such as _pcre_xclass(), which are internal to the library,
848            but external in the C sense, all had PCRE_EXPORT in their definitions.
849            This is apparently wrong for the Windows case, so I have removed it.
850            (It makes no difference on Unix-like systems.)
851    
852    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
853        of recursive calls to match(). This is different to MATCH_LIMIT because
854        that limits the total number of calls to match(), not all of which increase
855        the depth of recursion. Limiting the recursion depth limits the amount of
856        stack (or heap if NO_RECURSE is set) that is used. The default can be set
857        when PCRE is compiled, and changed at run time. A patch from Google adds
858        this functionality to the C++ interface.
859    
860    18. Changes to the handling of Unicode character properties:
861    
862        (a) Updated the table to Unicode 4.1.0.
863    
864        (b) Recognize characters that are not in the table as "Cn" (undefined).
865    
866        (c) I revised the way the table is implemented to a much improved format
867            which includes recognition of ranges. It now supports the ranges that
868            are defined in UnicodeData.txt, and it also amalgamates other
869            characters into ranges. This has reduced the number of entries in the
870            table from around 16,000 to around 3,000, thus reducing its size
871            considerably. I realized I did not need to use a tree structure after
872            all - a binary chop search is just as efficient. Having reduced the
873            number of entries, I extended their size from 6 bytes to 8 bytes to
874            allow for more data.
875    
876        (d) Added support for Unicode script names via properties such as \p{Han}.
877    
878    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
879        matching that character.
880    
881    20. When matching a repeated Unicode property with a minimum greater than zero,
882        (for example \pL{2,}), PCRE could look past the end of the subject if it
883        reached it while seeking the minimum number of characters. This could
884        happen only if some of the characters were more than one byte long, because
885        there is a check for at least the minimum number of bytes.
886    
887    21. Refactored the implementation of \p and \P so as to be more general, to
888        allow for more different types of property in future. This has changed the
889        compiled form incompatibly. Anybody with saved compiled patterns that use
890        \p or \P will have to recompile them.
891    
892    22. Added "Any" and "L&" to the supported property types.
893    
894    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
895        but give a compile time error if the value is greater than 0xff.
896    
897    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
898        accidentally not being installed or uninstalled.
899    
900    25. The pcre.h file was built from pcre.h.in, but the only changes that were
901        made were to insert the current release number. This seemed silly, because
902        it made things harder for people building PCRE on systems that don't run
903        "configure". I have turned pcre.h into a distributed file, no longer built
904        by "configure", with the version identification directly included. There is
905        no longer a pcre.h.in file.
906    
907        However, this change necessitated a change to the pcre-config script as
908        well. It is built from pcre-config.in, and one of the substitutions was the
909        release number. I have updated configure.ac so that ./configure now finds
910        the release number by grepping pcre.h.
911    
912    26. Added the ability to run the tests under valgrind.
913    
914    
915    Version 6.4 05-Sep-05
916    ---------------------
917    
918     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
919        "--" to be printed when multiple files were scanned, even when none of the
920        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
921        consider it to be a bug, and have restored the previous behaviour.
922    
923     2. A couple of code tidies to get rid of compiler warnings.
924    
925     3. The pcretest program used to cheat by referring to symbols in the library
926        whose names begin with _pcre_. These are internal symbols that are not
927        really supposed to be visible externally, and in some environments it is
928        possible to suppress them. The cheating is now confined to including
929        certain files from the library's source, which is a bit cleaner.
930    
931     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
932        file's purpose clearer.
933    
934     5. Reorganized pcre_ucp_findchar().
935    
936    
937    Version 6.3 15-Aug-05
938    ---------------------
939    
940     1. The file libpcre.pc.in did not have general read permission in the tarball.
941    
942     2. There were some problems when building without C++ support:
943    
944        (a) If C++ support was not built, "make install" and "make test" still
945            tried to test it.
946    
947        (b) There were problems when the value of CXX was explicitly set. Some
948            changes have been made to try to fix these, and ...
949    
950        (c) --disable-cpp can now be used to explicitly disable C++ support.
951    
952        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
953            backslash in a target when C++ was disabled. This confuses some
954            versions of "make", apparently. Using an intermediate variable solves
955            this. (Same for CPP_LOBJ.)
956    
957     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
958        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
959        necessary on certain architectures.
960    
961     4. Added a setting of -export-symbols-regex to the link command to remove
962        those symbols that are exported in the C sense, but actually are local
963        within the library, and not documented. Their names all begin with
964        "_pcre_". This is not a perfect job, because (a) we have to except some
965        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
966        available (and never for static libraries). I have made a note to try to
967        find a way round (a) in the future.
968    
969    
970    Version 6.2 01-Aug-05
971    ---------------------
972    
973     1. There was no test for integer overflow of quantifier values. A construction
974        such as {1111111111111111} would give undefined results. What is worse, if
975        a minimum quantifier for a parenthesized subpattern overflowed and became
976        negative, the calculation of the memory size went wrong. This could have
977        led to memory overwriting.
978    
979     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
980    
981     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
982        operating environments where this matters.
983    
984     4. Applied Giuseppe Maxia's patch to add additional features for controlling
985        PCRE options from within the C++ wrapper.
986    
987     5. Named capturing subpatterns were not being correctly counted when a pattern
988        was compiled. This caused two problems: (a) If there were more than 100
989        such subpatterns, the calculation of the memory needed for the whole
990        compiled pattern went wrong, leading to an overflow error. (b) Numerical
991        back references of the form \12, where the number was greater than 9, were
992        not recognized as back references, even though there were sufficient
993        previous subpatterns.
994    
995     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
996        versions of gcc, e.g. 2.95.4.
997    
998    
999    Version 6.1 21-Jun-05
1000    ---------------------
1001    
1002     1. There was one reference to the variable "posix" in pcretest.c that was not
1003        surrounded by "#if !defined NOPOSIX".
1004    
1005     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1006        the cross-check on the old pcre_info() function, for the benefit of the
1007        cut-down version of PCRE that is currently imported into Exim.
1008    
1009     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1010        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1011        patterns that start (?i) but I don't think that matters. The use of (?i) is
1012        just an example; this all applies to the other options as well.
1013    
1014     4. Since libtool seems to echo the compile commands it is issuing, the output
1015        from "make" can be reduced a bit by putting "@" in front of each libtool
1016        compile command.
1017    
1018     5. Patch from the folks at Google for configure.in to be a bit more thorough
1019        in checking for a suitable C++ installation before trying to compile the
1020        C++ stuff. This should fix a reported problem when a compiler was present,
1021        but no suitable headers.
1022    
1023     6. The man pages all had just "PCRE" as their title. I have changed them to
1024        be the relevant file name. I have also arranged that these names are
1025        retained in the file doc/pcre.txt, which is a concatenation in text format
1026        of all the man pages except the little individual ones for each function.
1027    
1028     7. The NON-UNIX-USE file had not been updated for the different set of source
1029        files that come with release 6. I also added a few comments about the C++
1030        wrapper.
1031    
1032    
1033  Version 6.0 07-Jun-05  Version 6.0 07-Jun-05
1034  ---------------------  ---------------------
1035    

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